They fly at iron - Samuel R Delany

When a peaceful nation of well-organized peasants is overrun by the army of an expanding industrialized neighbour, the people of iron must forge a pact with the strange and fearsome race of flying humans dwelling high above in the mountains.

In scenes of excellent bloodshed, the invaders are routed at the end - but the outcome is by no means obvious, despite the aid of a renegade invader, Lieutenant Kire, and, more significantly, of the winged people, regal, fierce, libidinous, leathery masters of the sky.

The gloriously strange fantasy world comes newly alive in Delany's masterful prose - the setting was first used by him in 1962 in a short story. He nudges into the light many less than obvious truths about character. His unique talent for getting inside physical sensations and making them tangible with words, significant in shaping outlook, is much in evidence and ensures that the strategies employed by both sides in the bloody conflict are nailbitingly uncertain.